OS 9B with Bellmouth Airhorn

[RaceMechaniX]

So I noticed OS came out with a trick airhorn for the heli motors and bought one to see if it would fit a OS 9B. Turns out it is roughly 1mm too large on the throat. The OS has a 17.5mm OD neck while the airhorn is 18.5mm ID. I machined a tube with the correct dimensions from some Delrin stock and make a simple piece to fill the gap. So now the 9B looks serious and will flow a little more air. The part number from Tower hobbies is: http://www3.towerhob...p?&I=LXBYZC&P=Z . The Throat lines up perfectly. Pretty easy to do to make your reliable OS9B flow closer to one of Charlie's Zoom Carbs.

View before the airhorn was pressed on:

View down the throat:

 

[Terry Keeley]

Cool!

 

[David Bryant]

what engine are you using this carb on?

 

[Koban Rado]

what engine are you using this carb on?

http://www.prestwich.ndirect.co.uk/techcarb.htm

 

[RaceMechaniX]

I have it for a CMB 80HR, but I also have a Zoom carb for that motor. I will likely save it for a 67HR when I pick one up eventually. TG

 

[XtremeRcBoats]

Very nice idea Tyler. I've got a CMB90 with an OS9b and might try this myself.

DId you already try it out and did you notice any difference?

 

[RaceMechaniX]

Paul, I just machined this last night so no tests yet. I expect it will function identically as a 9B would will a little more flow at top end. For a 67 motor there will likely be unnoticeable gains, but on an 80 or larger 90 I expect top end to improve.

 

[David Bryant]

how is the OS 9B carb comparing to the stock CMB 45VAC carb? Or the Zoom carb?

 

[RaceMechaniX]

I can't say against a 45 VAC carb, but in general O.S. carbs IMO are the gold standard for reliability/consistency, fit and finish. TG

 

[Steve Seebold]

Nice job Tyler. Didn't know you had it in you.

 

[David Bryant]

I can't say against a 45 VAC carb, but in general O.S. carbs IMO are the gold standard for reliability/consistency, fit and finish. TG

interesting, that's good to know.

 

[RaceMechaniX]

Steve, I used to have a very nicely equipped machine shop in Goleta where I worked before the equipment moved to TN. Most of the induction kits on the site I designed. http://www.borlainduction.com/Home/Home-FR.html

 

[Steve Seebold]

Steve, I used to have a very nicely equipped machine shop in Goleta where I worked before the equipment moved to TN. Most of the induction kits on the site I designed. http://www.borlaindu...me/Home-FR.html

Why on earth would anyone want to move from CA to TN.

 

[Hydro Junkie]

I would guess lower overhead and operating costs

 

[RaceMechaniX]

Ding Ding Ding, we have a winner. Yes, lower operating costs and huge tax incentives plus a 500,000sqft facility. Alex Borla of Borla Exhausts purchased TWM Induction several years ago and moved the equipment and the employees who wanted to move out to Johnson City, TN. Borla still has a R&D shop in CA. Johnson City is quite nice, just much quieter compared to CA. TG

 

[Charles Perdue]

Operator Error.........Brain mulfuctune..................

 

[Charles Perdue]

Steve, I used to have a very nicely equipped machine shop in Goleta where I worked before the equipment moved to TN. Most of the induction kits on the site I designed. http://www.borlaindu...me/Home-FR.html

Why on earth would anyone want to move from CA to TN.

Steve, some of us just want more out of life than California can offer. You have an open invitation to visit me sometimes in Tennessee. It may not change your mind, but I am sure that you will enjoy your visit. Charlie

 

[David Bryant]

Johnson City is quite nice, just much quieter compared to CA. TG

Goleta is uniquely nice, a laid-back suburb (if you will) of Santa Barbara...........

 

[David Bryant]

So, before I forget, does the O.S. 9B bolt directly onto a brand-new CMB .67HR or .80HR?

I have two new CMB .80HR engines, are the stock carb's okay? How are most folks running their engines (or carbs)? trying to find out what is best solution (being that their are no more Orlic or Zoom carbs available).

Also, what is I.D. of stock .67/.80HR carb?

Appreciate your input

 

[Ray Sametz]

http://www.intlwaters.com/index.php?showtopic=61940